Billionaire chocolate tycoon Petro Poroshenko has won Ukraine's presidential election outright in the first round, according to an exit poll.

The poll for Sunday's election, conducted by three respected Ukrainian survey agencies, found the tycoon won 55.9% of the vote.

In a distant second was former prime minister Yulia Tymoshenko with 12.9%. Full results are expected to be announced on Monday in the election that could be a critical step toward resolving Ukraine's crisis.